1. Field of the Invention
The invention is related to the field of memory devices, and in particular, to initialization of memory devices.
2. Description of the Prior Art
Electronic devices commonly employ some manner of memory. The memory may be used to store a control routine, store values to be used during operation, and/or store values to be used during initialization.
The memory may include solid state memory, i.e., memory formed of transistor devices. The memory may comprise a number of registers. Registers comprise a number of memory cells, and are commonly used by an associated processing system to hold values generated by a software routine executing on the processing system. In many electronic devices, a number of registers are initialized at power-up of the device, or upon a reset of the device. The initialization may include loading of any manner of common or desired data values into the registers. The initialization enables the electronic device to consistently operate in a known manner.
FIG. 1 shows an electronic device constructed according to a prior art initialization approach. In the prior art, the initialization values are stored in a non-volatile memory, such as a read-only memory (ROM), for example. The initialization values, such as the bytes AAh (hexadecimal) and 00h in the example shown, are read out of the non-volatile memory in a conventional manner. The initialization values are transmitted serially to the memory and programmed into corresponding registers.
The prior art approach has several drawbacks. The serial reading out and programming of the initialization values takes significant time to perform. The required time grows with the number of registers to be initialized. The prior art approach was relatively workable when the number of registers to be programmed was small. As electronic devices have become more sophisticated, they have included larger and larger register sets, and as a result the initialization time has become longer and longer. In addition, for purposes of manufacturing economy and product flexibility, many electronic devices are now capable of operating in a plurality of modes, and each mode may require a different set of initialization values. Therefore, in order to configure the electronic device in different modes, the initialization values in the non-volatile memory must be re-programmed, incurring extra time and cost. These factors have made memory initialization problematic.